Fuel injection system



Aug. 22, 1961 T-. M. BALL FUEL INJECTION SYSTEM Filed July 50, 1958 INVENTOR. Tia/714$ M34 ZZ WWW 2,997,035 FUEL INJECTION SYSTEM Thomas M. Ball, Bloomfield Hills, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed July 30, 1958, Ser. No. 751,921 11 Claims. (Cl. -123-119) This invention relates to a fuel injection system of the type disclosed in the related copending application of Thomas M. Ball et al., Serial No. 751,999, filed July 30, 1958, and assigned to applicants assignee, for use on internal combustion engines and relates in particular to a novel means for distributing a fuel in air mixture to the injection nozzles of said system.

Fuel injection systems have been conventionally provided with various types of fuel metering means which meter fuel to the fuel injection nozzles in accordance with various engine parameters such as engine speed and load. Means have also been provided on the injection nozzles for forming a preliminary mixture of fuel in air prior to its being injected into the engine intake manifold or cylinders. This means usually consists of an air bleed in the nozzle which allows air to be sucked or pumped under pressure into the fuel stream.

With such systems liquid fuel is usually first metered according to the aforesaid engine parameters and is then directly distributed through a plurality of separate conduits to the individual fuel injection nozzles strategically placed on the intake manifolds for each cylinder. A serious problem presented by this mode of distribution is that vaporization of the volatile liquid fuel occurs at the downstream or low pressure side of the fuel metering means due to the drop in pressure across the metering orifices and also occurs in the fuel conduits due to excessive engine heat. Subsequent equal distribution of fuel to the separate nozzles becomes very difficult if not impossible because of the variable volume of fuel vapor which volume is particularly prominent on hot days and under driving conditions which cut down the efficiency of the engine cooling system such as idling and stop and go city driving. Another problem encountered in distributing liquid fuel directly from the metering unit to the nozzles is that pressure variations of heads caused by air pulsations within the manifold and applied to the distributed fuel at the nozzle orifices are transmitted back to the metering unit and cause therein undesirable and unregulatable metering effects.

The present invention eliminates these problems by providing the aforementioned systems with a fuel and air mixing pump interposed between the metering unit and the fuel injection nozzles. This pump is adapted to receive metered fuel and clean air, thoroughly mix them and force the mixture under substantially constant pressure through a plurality of conduits to the individual fuel injection nozzles. Should further vaporization of the dispersed fuel occur, the slight resultant change in volume does not seriously impair the functioning of the metering means. The pump may conveniently be a constant delivery rotary type which will provide enough mixing or atomizing air to thoroughly disperse the maximum amount of fuel required by the engine. The quantity of air provided by the pump for the mixing operation is relatively small compared to the quantity of air required for combustion and does not noticeably affect the normal fuel-air consumption ratio.

The vaporization problem is further solved herein by combining with the pump a return flow fuel metering system which has the inherent characteristics of allowing the fuel Within the system to be maintained at a higher pressure than would be possible with direct inlet metering.

trite States Patent The combination of these two features provides a fuel injection system which obviates to a large degree the metering and distribution problems caused by fuel vaporization.

An object is to provide a fuel injection system having a minimum susceptibility to the undesirable effects of fuel vaporization and intake manifold pressure pulsations.

Another object is to provide a fuel injection system with a means capable of producing and delivering a thoroughly mixed dispersion of fuel in air to the engine over the complete speed and load range of said engine.

Another object is to provide a fuel injection system having a fuel and air mixing pump operable in conjunction with a return flow fuel metering unit which system is substantially unhindered by fuel vapor formation and can deliver the proper amount of fuel to the engine under hot engine conditions.

Further objects and advantages will become apparent from the following specification and accompanying drawings, in which:

FIGURE 1 represents a diagrammatic view of the complete fuel injection system; and

FIGURE 2 represents a cross sectional view of a rotary type pump utilizable in the present system.

In FIGURE 1 is shown a fuel injection metering system for an internal combustion engine comprising a speed sensor 10, a load sensor 12, and an accelerator pump 14. The speed sensor is provided with four housing portions 16, 18, 20, and 22 separated from each other by diaphragms 24, 26, and 28 respectively to provide chambers 30, 32, 34, and 36. Chamber 30 communicates with a fuel tank 38 through conduit 40. A fuel pump 42 in said conduit supplies a constant volume of fuel under pressure through filter 44 to chamber 30 during the operation of said engine regardless of the engine load or speed. The pressure of the fuel supplied by the pump is sufliciently high to retard vaporization in chambers 30 and 72 under engine operating conditions of high heat and light load. A return flow metering orifice 46 in said housing portion 16 connects chamber 30 with a return flow conduit 48 which communicates with the inlet check valve 50 of accelerator pump 14. A return flow metering needle 52 having a tapered point 54 is secured to each of said diaphragms 24, 26, and 28 by suitable grommets 56.

A flyweight support 58 pivotally supports flyweights 6d and 62 and is secured to a flexible shaft 64 which is operatively connected to the engine to rotate at a speed directly proportional to engine speed. Flyweights 60 and 62 have projections 66 and 68 respectively thereon which abut the end of needle 52 as said flyweights pivot outwardly in response to rotation of shaft 64 to urge needle 52 toward orifice 46 against the force applied in the opposite direction against diaphragm 24 by the fuel in chamber 30.

A conduit 70 connects chamber 30 to the upstream chamber 72 of the load sensor which upstream chamber communicates with a downstream fuel distribution chamber 74 of the load sensor across a load metering orifice 7 6. A load metering needle 78 having tapered end 79 is positioned in orifice 76 and is operatively connected to piston 80 reciprocably mounted in cylinder 82, which cylinder operatively communicates through conduit 86 with the low pressure portions of each intake manifold 84. Manifolds 84 connect to cylinder heads 87 of engine 89. Low pressure transmitted through conduit 86 will cause piston 80 to be drawn upwardly against the force of spring 88 to thereby urge the tapered end 79 of needle 78 into closer proximity to the sides of orifice 76 and conversely high pressure in the intake manifolds will tend to urge needle 78 to a more open position with respect to orifice 76. A metered fuel feed conduit 90 extends from chamber 74 of the load sensor to a fuel-air premix chamber 92 having an air inlet 94 adapted to bleed directly to the atmosphere or be connected to a suitable air pump (not shown). Chamber 92 discharges to the inlet 93 of a rotary vane type pump 96, see FIGURE 2, having a housing 98, a slotted rotor 100 eccentrically mounted therein and a plurality of slippers 102 slidable in the slots 104 of said rotor and adapted to be thrown outwardly against the housing by centrifugal force as the rotor rotates counterclockwise to pick up fuel and air by a shearing action from inlet 94, mix them, and discharge the mixture from outlet 106 into a distribution gallery 108. Other pumps such as fan type blowers could be used to give the desired mixing and pressurizing effect but the type of pump shown appears to be the most desirable. A plurality of nozzle feed conduits 110 extend from chamber 108 to an equal number of fuel injection nozzles 112 located upstream of the throttle valves 114 of the individual intake manifold sections 84. The atomizing air supply to the nozzles 112 may be obtained from pump 116 having intakes 118 and 120 and transmitted to the branch air conduits 122 of said nozzles by a main air conduit 124. Chamber 74 of the load sensor is connected to chamber 32 of the speed sensor by conduit 126 to provide an adjustment of the return flow metering needle 52 with respect to orifice 46 based on the pressure differential existing across orifice 76 of the load sensor.

An idle boost conduit 128 communicates with one of said manifold sections 84 at a point adjacent the edge of the throttle valve 114 of that section and with the chamber 34 of the speed sensor. An air bleed valve 130 in conduit 128 is provided to regulate the pressure transmitted to chamber 34 from said manifold section during idling of the engine in order to regulate thereby the speed of the engine at idling. Under normal idling conditions the pressure in chamber 34 is lower than in chamber 36 which is vented to the atmosphere and said pressure in chamber 36 tends to urge the needle 52 toward orifice 46 to retard the flow of return fuel therethrough and provide a suflicient fuel supply for idling. The requirement of this additional boost to needle 52 is due to the fact that at slow engine speed the flyweights are not fiung outwardly with suflicient force to negate the frictional resistance of the needle 52 to movement.

The accelerator pump 14 having an inlet check valve 50 and an outlet check valve 132 receives fuel through said inlet valve into chamber 134 from which the return fuel continues through the return flow conduit 136 back to the tank. The depression of the accelerator will force piston 138 of said pump 14 downwardly to force fuel through check valve 132 and through conduit 140 directly to the downstream chamber 74 of the load sensor.

The operation of the fuel injection metering system will be described in relation to a change in static engine operating conditions, that is, constant engine speed and load. Under said static operating conditions, the combined forces exerted by flyweights 60 and 62 and the fuel in chamber 32 is balanced by the force exerted by the fuel in chamber 30 and the return flow metering member 52 is maintained stationary at a distance away from orifice 46. In this static condition, the amount of fuel delivered to chamber 74 of the load sensor is constant and is equal to the constant amount of fuel being delivered to the system by the pump 42 less the constant amount of fuel being returned to the fuel tank through the return flow conduit 48. If this static condition represents the engine during normal driving speed, the pressures in chambers 36 and 34 have no noticeable affect on the operation of the unit and may be disregarded. It is only during idling and very low engine speeds that the pressure differential across diaphragm 28 becomes significant.

As the throttle valves 114 are moved to a more open position by the depression of the engine accelerator, an increase in manifold pressure is transmitted to the load sensor piston through conduit 86 and moves said piston down to thereby move the load metering needle 78 to a more open position with respect to the load metering orifice 76. The pressure differential existing across said orifice is consequently decreased as more fuel is allowed to flow into chamber 74. This decrease in pressure differential causes the flow through orifice 76 to deviate from the desirable flow which is substantially directly proportional to engine speed. To correct this condition and bring the pressure differential across said orifice up to a value where the flow of fuel therethrough is substantially directly proportional to engine speed, the fuel pressure in speed chamber 30 and load sensor chamber 72 communicating therewith is increased. This increase in pressure is accomplished by moving the return flow metering member 52 closer to orifice 46 by the increased force transmitted by the fiywheights 60 and 62 as the engine speed is increased and by the increased pressure in chamber 32 caused by the increased flow of fuel into the downstream chamber 74 of the load sensor. When the forces transmitted by said flyweights and the fuel in said chamber 32 once again balance the force transmitted in the opposite direction by the fuel in chamber 30, the flow of fuel through orifice 76 will be substantially directly proportional to the speed of the engine and will correspond to the flow of combustion air into the intake manifold.

The metered fuel passes from the downstream chamber of the load sensor through the metered fuel conduit into the premix chamber wherein it is brought into contact with air. This premix chamber insures that at high fuel flow enough air will come in contact with the fuel within the pump to atomize or disperse the fuel in the air and produce a substantially homogeneous mixture. Pump 96 operating at a set velocity and capacity mixes the incoming fuel and air in the various proportions determined by the variations in fuel output of the metering system, and forces the mixture into the distribution chamber 108 and out through the nozzle feed conduits to the separate injection nozzles. It is noted that at low fuel consumption engine operation the proportion of air mixing with the fuel in the pump is greater than at high fuel consumption since the capacity of the pump remains constant, however the capacity of the pump is such that enough air may be provided in the pump to disperse in air the maximum fuel output of the metering system at the maximum fuel consumption operation of the engine.

The nozzles used in conjunction with the described fuel metering system and mixing pump may be of various types such as that used for direct injection of the mixture into the manifold or for the further atomization of the mixture within the nozzles which latter type is shown herein.

I claim:

1. In a fuel injection system for an internal combustion engine having an intake manifold, a fuel feed conduit communicating with said manifold and a fuel supply, fuel metering means in said fuel feed conduit for regulating the flow of fuel to said manifold in accordance with engine requirements, a pumping means in said conduit downstream of said metering means, said pumping means having a common fuel and air inlet and a common fuel and air mixture outlet, said outlet communicating with said engine manifold through said fuel feed conduit, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and distribute the resultant mixture under pressure to said engine manifold.

2. In a fuel injection system for a multicylinder internal combustion engine, a fuel feed conduit communicating with said engine and a fuel supply, fuel metering means in the fuel feed conduit for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a pumping means in said conduit downstream of said metering means, said pumping means having a common fuel and air inlet and a common fuel and air mixture outlet, said outlet communicating with each cylinder of said engine through separate branches of said fuel feed conduit, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and distribute the resultant mixture under pressure to the separate cylinders of said engine.

3. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feed conduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a pumping means downstream of said metering means and communicating therewith through a metered fuel conduit, said pumping means having a common fuel and air inlet and a common fuel and air mixture outlet, said outlet communicating with each cylinder of said engine through separate branch conduits, said pumping means being a :onstantspeed rotary vane pump adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and distribute the resultant mixture under pressure to the separate cylinders of said engine.

4. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feed conduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a premix :hamber downstream of said metering means and communicating therewith through a metered fuel conduit;

said pumping means having a common fuel and air inlet communicating with said outlet of said premix chamber, a common fuel and air mixture outlet on said pumping means communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and distribute the resultant mixture under pressure to the separate cylinders of said engine.

5. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feed conduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a premix chamber downstream of said metering means and communicating therewith through a metered fuel con- :luit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means, said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery.

6. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feed conduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a premix chamber downstream of said metering means and communicating therewith through a metered fuel con- :luit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, said pumping means having parts thereon for rapidly moving and striking the incoming fuel and air from the premix chamber at an angle substantially transverse to the direction of the flow of said fuel and air, a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means, said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted-to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery.

7. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feedconduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a premix chamber downstream of said metering means and comp municating therewith through a'metered fuel conduit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, said pumping means having parts thereon for rapidly moving and striking the incoming fuel and air from the premix chamber at an angle substantially transverse to the direction of the ilow of said fuel and aid, said rapidly moving parts comprising slipper members reciprocably mounted on a rotor, said rotor being eccentrically mounted in a cavity in said pumping means, a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means, said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery.

8. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means, a fuel feed conduit communicating with said metering means and a fuel supply, said fuel metering means being adapted for regulating the flow of fuel to said engine in accordance with engine speed and load requirements, a premix chamber downstream of said metering means and communicating therewith through a metered fuel conduit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, said pumping means having a plurality of parts thereon mounted for rapid movement in a path substantially transverse to the direction of the flow stream of fuel and air into said pumping means, each of said parts having a surface thereon responsive to said rapid movement to shear a portion of said fuel and air from said flow stream and create a turbulence in said portion to form an intimate mixture of the fuel in air and force said mixture under pressure through a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means, said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery.

9. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means comprising a speed metering unit responsive to changes inengine speed to vary the flow of fuel to said engine and a load metering unit responsive to changes in intake manifold pressure to vary the flow of fuel to said engine, a fuel feed conduit communicating with said metering means and a fuel supply, a premix chamber downstream of said metering means and communicating therewith through a metered fuel conduit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, said pumping means having a plurality of parts thereon mounted for rapid movement in a path substantially transverse to the direction of the flow stream of fuel an intimate mixture of the fuel in air and force said mixture under pressure through a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means, said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery.

10. In a fuel injection system for a multicylinder internal combustion engine, fuel metering means comprising a speed metering unit responsive to changes in engine speed to vary the flow of fuel to said engine and a load metering unit responsive to changes in intake manifold pressure to vary the flow of fuel to said engine, said speed metering unit having return flow metering means therein communicating with a fuel supply, a fuel feed conduit communicating with each of said metering units and said fuel supply, a fuel pump in said feed conduit for supplying fuel under pressure to said speed metering unit, a premix chamber downstream of said metering means and communicating therewith through a metered fuel conduit, a pumping means having a common fuel and air inlet communicating with said common fuel and air outlet of said premix chamber, said pumping means having a plurality of parts thereon mounted for rapid movement in a path substantially transverse to the direction of the flow stream of fuel and air into said pumping means, each of said parts having a surface thereon responsive to said rapid movement to shear a portion of said fuel and air from said flow stream and create a turbulence in said portion to form an intimate mixture of the fuel in air and force said mixture under pressure through a common fuel and air mixture outlet on said pumping means, a fuel distribution gallery having a fuel and air mixture inlet connected to said outlet on said pumping means,-said gallery communicating with each cylinder of said engine through separate branch conduits, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and force the resultant mixture under pressure into said fuel distribution gallery and through said separate branch conduits to the engine.

11. In a fuel injection system for an internal combustion engine having an intake manifold, fuel feed conduit means communicating with said intake manifold and a fuel supply, fuel metering means associated with said conduit means for regulating the flow of fuel therethrough to said manifold in accordance with engine requirements, pumping means associated with said conduit means and having a metered fuel inlet, and an air inlet, and a common fuel and air mixture outlet, said mixture outlet communicating with said engine intake manifold through said fuel feed conduit means, said pumping means being adapted to thoroughly mix metered fuel with air throughout the speed range of said engine and distribute the resultant mixture under pressure to said engine intake manifold.

UNITED STATES PATENTS References Cited in the file of this patent 1,802,848 Summers Apr. 28, 1931 1,894,510 Ensign Jan. 17, 1933 

